All of them. With the caveat that when most people refer to 4chan they're referring to /b/, and that that isn't accurate, there really aren't many sites that /b/tards like. They tend to believe (rightly, imho) that every site takes itself too seriously and every community has an unwarranted sense of self-importance. That was generally the motivation behind most of the raids they did. At least, it used to be. It's summer right now so average quality is expected to be low, but a perusal of /b/ really does leave the impression that there aren't many original /b/tards left.
The sites /b/tards hate most:
-reddit (although there's a huge overlap in users, many /b/tards see it as a "sanitized" /b/ where funny things are reposted without anyone doing the work of making them in the first place)
-ebaumsworld (back in the day)
-knowyourmeme/icanhazcheezburger/all the other sites capitalizing off /b/'s memes
-facebook/myspace/deviantart/twitter/every other site whose primary use case seems to be people stroking their ego
All of them. With the caveat that when most people refer to 4chan they're referring to /b/, and that that isn't accurate, there really aren't many sites that /b/tards like. They tend to believe (rightly, imho) that every site takes itself too seriously and every community has an unwarranted sense of self-importance. That was generally the motivation behind most of the raids they did. At least, it used to be. It's summer right now so average quality is expected to be low, but a perusal of /b/ really does leave the impression that there aren't many original /b/tards left.
The sites /b/tards hate most:
-reddit (although there's a huge overlap in users, many /b/tards see it as a "sanitized" /b/ where funny things are reposted without anyone doing the work of making them in the first place)
-ebaumsworld (back in the day)
-knowyourmeme/icanhazcheezburger/all the other sites capitalizing off /b/'s memes
-facebook/myspace/deviantart/twitter/every other site whose primary use case seems to be people stroking their ego